1. Field of the Invention
The present invention relates generally to table soccer or fussball game apparatus, and more particularly relates to the fabrication of playing balls used in table soccer or fussball games.
2. History of the Prior Art
A table soccer or fussball game typically comprises. an elevated, open-topped elongated rectangular table structure having a bottom wall with a playing surface formed on its top side. The playing surface is peripherally bounded by an opposite pair of upstanding table end walls and an opposite pair of upstanding table side walls. Spaced apart along the length of the table are a series of elongated, parallel actuating rods which extend transversely to the length of the playing surface and are elevated with respect thereto. The opposite ends of each rod are received in and extend through an opposite pair of side wall bearing structures which permit the rod to be rotated and/or axially translated relative to the playing surface.
Molded plastic playing figures are suitably anchored to the actuating rods for rotation and axial translation with their associated rod, and are provided at their lower ends with specially configured foot portions. With a playing figure in its upright vertical position its foot portion is positioned somewhat above the playing surface, whereby each of the playing figures may be rotated through a full 180.degree. arc if desired.
For each player, the object of the game is to use his playing figure foot portions to rollingly propel a playing ball lengthwise along the playing surface, past the opponent's playing figures and into the opponent's goal area at an end of the playing surface. Such lengthwise movement of the ball along the playing surface (using a basic shot technique) is accomplished by appropriately aligning a playing figure with the ball and then rotating the playing figure to bring its foot portion sharply into contact with the ball. Other shot techniques may be utilized, and the ball may be laterally "passed" from one playing figure to another using their foot portions.
As played by skilled and experienced players, the game of table soccer or fussball is one of considerable intricacy and precision, with ball control accuracy being of paramount importance. In an effort to provide and maintain the ability to precisely control ball shooting and passing accuracy, considerable design effort has been expended over the years to improve the structural precision, longevity and playing consistency of various table soccer/fussball game components such as the playing surface, the rod bearing structures, the playing figures and their critical foot portions, and resilient side bumper structures used to protect the outermost playing figures on each actuating rod.
However, surprisingly few changes have been made over the years to a critical element of ball control accuracy--the playing ball itself. Accordingly, the playing ball is now generally seen to be one of the weaker links in the overall structural game component chain which must cooperate to provide optimum playing accuracy and consistency.
Typical table soccer/fussball game playing balls now in use are conventionally molded, generally to their finished spherical size, utilizing a blend of different thermoplastic materials-typically a relatively "hard" first thermoplastic material and a relatively "soft" second thermoplastic material. Under conventional design theory, this blending of different thermoplastic materials has heretofore been deemed necessary in order to provide the finished playing balls with a desirable combination of resiliency and mechanical toughness, along with other physical characteristics, which neither of the individual thermoplastic materials could provide by itself. After molding, the conventional dual material playing balls are subjected to a surface finishing tumbling process, to remove the usual molding flash and gate projections therefrom, thereby readying the balls for play. Alternatively, conventional table soccer/fussball game playing balls are molded from a single thermoplastic material to which a foaming agent is added in an effort to reduce the sphericity deviations caused by non-uniform cooling shrinkage associated with the molding process.
Despite the wide acceptance of these conventional playing ball fabrication methods, the playing balls resulting therefrom are subject to a variety of well known, and heretofore unavoidable, problems, limitations and disadvantages. For example, the normal nonuniform cooling shrinkage problem associated with plastic molding processes in general tends to be aggravated, via cross-contamination, by the use of two different thermoplastic materials in the molded balls. The finished balls are thus, to varying degrees, out-of-round to an extent such that they undesirably tend to stray from their intended shot or passing paths along the playing surface.
In the case where the ball is molded from a thermoplastic material to which a foaming agent has been added, the resulting out-of-roundness is somewhat reduced but still exists to a extent causing the ball to stray from its intended roll path. Additionally, the presence in the molded ball of the previously added foaming agent tends to significantly degrade the desired physical and playing characteristics of the ball.
During the initial portion of the playing life of a given ball fabricated by either of these conventional techniques, its tendency to stray from its intended roll path is somewhat lessened by the roughened exterior surface thereon, created during tumbling of the ball, which helps the ball to grip the playing surface and somewhat ameliorate the trueness of the ball's rolling path along the playing surface. However, this beneficial effect of the roughened surface quickly dissipates as the roughness is relatively rapidly worn away during play.
Conventionally fabricated playing balls of these types are also undesirably subject to two types of inconsistency. First, there tends to be inconsistencies in both physical and playing characteristics from one mold "batch" of balls to another (and often shot-to-shot inconsistences as well). Accordingly, it is a frequent occurrence for one ball to "play" markedly differently from another ball, whether the two balls are from the same mold batch or from different mold batches.
The second type of inconsistency is the often marked variation of playing characteristics of a given ball during its playing life. Simply stated, conventionally fabricated playing balls do not retain their "like new" playing characteristics for very long.
Another well known disadvantage of conventionally fabricated table soccer/fussball game playing balls is that they tend to wear out with surprising rapidity, particularly during strenuous play, and must be frequently replaced. Despite attempts, for example through the blending of different thermoplastic materials, to forestall such wearout, conventionally fabricated playing balls are quite susceptible to surface abrasion and gouging which diminishes their playing lives and aggravates their already undesirable rolling eccentricities.
It can readily be seen from the foregoing that it would be highly desirable to eliminate, or at least substantially reduce, the above-mentioned problems, limitations and disadvantages heretofore associated with conventionally fabricated table soccer/fussball game playing balls, and it is accordingly an object of the present invention to do so.